Accessibility to Vacant Activities: a Novel Model of Destination Choice
LEURENT F, INRETS, France
The spatial distribution of trips from origin zones to destination zones is usually modelled by physical analogy (eg. gravity model) or by discrete choice i?om among destination zones. In order to improve the microeconomic interpretation, Koenig (1974) an
The spatial distribution of trips from origin zones to destination zones is usually modelled by physical analogy (eg. gravity model) or by discrete choice i?om among destination zones. In order to improve the microeconomic interpretation, Koenig (1974) and Cochrane (1 975) have introduced a model of choice from among individual activities, in which it is assumed that (i) all activities have independent, identically distributed random utilities, and (ii) an activity serviced to a consumer is stiU available to other ones.
The purpose of the paper is to put forward a novel model of choice from among individual activities, called AVA for Accessibility to Vacant Activities. In AVA it is assumed that each activity has a gross value same for all consumers, and that each consumer chooses the best vacant activity, i.e. the one with maximal net value affer subtraction of the transport cost. Thus the distribution of trips eom origins to destinations results from the individual assignment of activities to consumers.
The paper contains four parts. First AVA's assumptions are introduced and discussed. Then their consequences are analyzed in the binary case. The gravity model is obtained as a special case, assuming exponentially-distributed utilities for activities in every destination zone. Next we address the general case with several origin and destination zones; we formulate the model as the solution of a concave maximition program, ofwhich the objective function represents the consumer surplus. This is further extended to elastic demand and congested transport. Lastly AVA is compared to other trip distribution models, with emphasis on the Koenig- Cochrane model.
Association for European Transport